by Michelle Healy, USA TODAY

by Michelle Healy, USA TODAY

In a new, updated policy statement, the nation's largest pediatricians group says that civil marriage for same-sex couples -- as well as full adoption and foster care rights for all parents, regardless of sexual orientation -- is the best way to ensure legal and financial security for children in these families.

"Children thrive in families that are stable and that provide permanent security, and the way we do that is through marriage," said Benjamin Siegel, co-author of the American Academy of Pediatrics policy statement. The group "believes there should be equal opportunity for every couple to access the economic stability and federal supports provided to married couples to raise children." Siegel is a pediatrics professor at Boston University School of Medicine.

The new policy statement, published online Thursday, is in the April issue of the journal Pediatrics.

In 2002 and again in 2010, the 60,000-member association supported second-parent adoption by same-sex partners as a way to protect children's right to maintain relationships with both parents, eligibility for health benefits and financial security. The new policy statement and an accompanying technical report adds recommendations in support of civil marriage for same-sex couples; adoption by single parents, co-parents or second parents regardless of sexual orientation; and foster care placement regardless of sexual orientation.

The statement says that an extensive body of scientific research documents that there is no cause-and-effect relationship between parents' sexual orientation and children's well-being.

Multiple studies attest to the healthy development of children of same-sex couples when the child is wanted, the parents have a commitment to shared parenting, and the parents have strong social and economic support, the statement says.

The statement names other national medical and health groups that have said they support marriage equality, including the American Psychological Association; the American Psychiatric Association and the American Academy of Family Physicians.

Others that the statement says "support gay and lesbian parenting and the nurturing of children" include: the American Academy of Child and Adolescent Psychiatry; the American College of Obstetrics and Gynecology and the American Medical Association.